5 year check up

Christopher had his 5year check up yesterday.  Thankfully he didn't need any shots! The main concern of coarse was his behavior.  He is still very defiant and argumentative.  He can be very aggressive and violent.  He has food issues that have gotten worse over the past month.  He is still having trouble sleeping, but now worse than ever.  He asks every night when its going to be morning, and complains that he forgot how to fall asleep!  It takes him 2 to 4 hours to fall asleep.  We are considering medication, but first we are going to try some vitamins for a month and see what happens.  I am supposed to get the following: focus factor, Behavior balance DMG, and Bioglan kids smart.  I am thinking about also getting melatonin to help him sleep.  I have always wondered if he slept through the night would his behavior be better?  My guess is yes. If I don't get enough sleep I can behave like a monster to.  The doctor says that many of the problems we describe are sensory and wants him to go back to Occupational Therapy (OT).  We did this before with little noticeable improvement, but that was almost 2 years ago (I think)!   We are also going to go to a psychologist.  The hardest part is how are we supposed to respond to him.  We don't want to do harm (physically or mentally).  However, if we don't do something soon eventually he will be to big and we won't be able to control him.  Now I often have to pick him up and carry him to his room.  I have had to use all my strength before to keep him from attacking his sister! 

Now it sounds like he is a horrible kid.  He is not! He is a very smart and loving person.  He just cannot help it.  He gets upset, frustrated, or angry and cannot control how he acts.  He loves to help and can be very loving.  He usually isn't gentle but that isn't on purpose either.  I always say he is basically 2 kids!  My angel and my demon all in one, but you never know what your gonna get!  And they can switch on you in an instant. 
P.S.  If any one has any experience with these medications or any advice please don't hesitate to leave me a comment!  At age 5 we really don't want to start medication.  I don't think the vitamins could do any harm, but I guess you never know.  I'm not sure if any long term research has been done on them.  I am just gonna trust my doctor, because I do trust him, and I am in way over my head!